There are a number of applications in which conversion is required between DC power and AC power. The applicant's earlier International patents, published under numbers WO2012/016285 and WO2013/023248, describe such systems having improved methods of performing this conversion.
The systems described provide for creation of an AC signal suitable for power supply, or injection into mains power from DC sources consisting of a string of modules each connected to a DC power source. The modules are switched in an out of series in order to form a stepwise approximation of an AC signal and further compensation is performed to allow the signal to more closely resemble a desired AC signal.
Such systems rely on connectors to safely and efficiently carry high currents between modules. Solder joints, crimps and connection of connector pins can lead to failures that are hard to detect before breakdown occurs and difficult to locate after partial or total failure. Due to the series connected nature of such systems, identifying the location of intermittent faults may be problematic.
It is therefore desirable to provide a method for detection of faults within the connectors of such series connected power conversion systems.